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<P>Core SSFNet classes for modeling and simulation of network elements
(hosts, routers, network interfaces, links) and configuration of
arbitrarily complex network topologies.

<P>The principal network elements modeled by package SSF.Net are:</P>
<OL>
  <LI><CODE>Net</CODE>
  <LI><CODE>Host</CODE> and <CODE>Router</CODE>
  <LI><CODE>NIC</CODE>
  <LI><CODE>link</CODE>
</OL>
<P>
Class <CODE>Net</CODE> loads all the model's DML configuration files and controls
the orderly instantiation of the entire model: hosts and routers with their protocols,
networks connecting hosts and routers, as well as the placement of monitoring infrastructure,
scheduling of traffic scenarios, and multiple random number streams.
The DML model configuration is hierarchical, and allows recursive composition of larger networks
from pre-configured sub-networks.</P>

<P>Class <CODE>Net</CODE> also controls the automatic assignment of IP addresses
to all networks and interfaces in a model, following the CIDR guidelines.

<P>Class <CODE>Host</CODE> (actually derived from SSF.OS.ProtocolGraph) is fully
configurable and can support any graph of network protocols. Minimally,
this must include IP (which provides packet forwarding) and at least one <CODE>NIC</CODE>.
A <CODE>Router</CODE> is a special case of a <CODE>Host</CODE> with multiple
<CODE>NIC</CODE>s, and possibly a specialized protocol graph.</P>

<P>Class <CODE>NIC</CODE>  (Network Interface Card) derived from
<CODE>ProtocolSession</CODE> is a bottom-level pseudo-protocol that maintains
a pair of buffered SSF in/outChannels to the world outside the protocol graph.
<CODE>NIC</CODE> has various configuration options for physical link characteristics,
packet queueing and scheduling, that may be configured from a
 matching DML description. </P>

<P> The interface <CODE>packetQueue</CODE> establishes a common framework for
the implementation of various packet queue models.

<P> The interface <CODE>packetQueueMonitor</CODE> provides a common framework for
runtime monitoring of the dynamics of queues in a model.

<P>Class <CODE>link</CODE> models link-layer connectivity among a set of
attached interfaces. A link with more than two attached interfaces
performs collision-free level-2 switching of IP packets sent on any attached interface.</P>

<P>The package <CODE>SSF.Net</CODE> also provides classes implementing the IP forwarding
tables.</P>

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